The short version: I'm loading over 1 billion breached accounts into HIBP. These are from 2 different "combo lists", collections of email addresses and passwords from all sorts of different locations. I've verified their accuracy (including my own record in one of them) and many hundreds of millions of the
WHY THIS IS IMPORTANT
Pretty much your whole life is online and digitize today. Your only protection from crooks is strong passwords that you never reuse. This article provides in depth discussion on the millions of passwords that are being sold for few dollars on the dark web. It should help you understand why this is important and what to do to be more secure.